Treatment of artificial filaments and like products



Patented a. 21, 1936 UNITED- sr rEs PAT F TREATMENT OF ARTIFICIAL AND LIKE PRODUCTS No Drawing. Application May 13, 1932, Serial No. 611,240. In Great Britain June 18, 1931 v l-Claims. This invention relates to processes for improving the properties, and more particularly the 4 extension of artificial filaments, threads, yarns, ribbons and the like made of or containing cellulose acetate or other cellulose esters or ethers.

As is well known, for purposes of textile operations and particularly weaving, knitting and twisting, it is desirable that filaments, threads, yarns, or other products shall have an extension, 1. e. an increase in length at the breaking point, of to 12 or 15% or more. In the ordinary dry spinning of cellulose acetate or other esters or ethers, the production of such materials pre-- sents no difiiculties, and the filaments obtained customarily have an extension considerably exceeding the values indicated. when such dry spun filaments or other products are stretched, with or without the aid of assisting agents, as

- described for example in U. S. Patent No.

1,709,470, U. S. patent applications S. Nos. 378,684 filed 16th 'July, 1929 and 573,424 filed 6th November, 1931, and U. S. patent application S. No. 605,184 fi'led April 14, 1932 corresponding to British application No. 13373/31 filed 6th May, 1931, considerably increased tenacities are obtained and other properties of the materials are improved. 0n the other hand in some cases filaments are obtained which have relatively low extensions. Again, in the wet spinning of cellulose. acetate or other-cellulose esters or ethers, as,'ior example, by the processes described in U. S. Patents Nos. 1,465,994 and 1,467,493, U. S.-patent applications S. Nos. 402,785 filed 26th October,

1929, 418,414 filed 3rd January, 1930 and 437,423 filed 20th March, 1930, U. S. patent application S. No. 601,043 filed March 24, 1932 corresponding to British application No. 13998/31 filed 12th May, 1931,and British Patents Nos. 340,436 and 340,437, filaments of high tenacities, for example tenacities of 2 to 2% or 3 or moregrams perdenier are directly obtainable. Some of these filaments also have relatively low extensions. It-is the object of the present invention to treat all such filaments or other products of relatively low extension so as to increase the extension or the same and render them more amenable to textile processing, and at the same time to retain, or retain in a substantial degree, the high tenacities which in general characterize the said products. I

According to the present invention filaments, yarns, ribbons and other products made 01 or containing cellulose acetate or other esters or ethers of cellulose, and having a relatively low extension, are treated with shrinking agents soas to increase their extension. In general the agents which may be used are agents which have a swelling or solvent action upon the cellulose derivative.

It is preferable to effect the treatment with the shrinking agents in such a manner that the filaments or other products are not subjected to any tension at all or are only subjected to a comparatively moderate tension. If, however, relatively high tensions are employed, it is desirable that the tension should be subsequently decreased or removed altogether so that a subsequent shrinkage of the material is still possible, for example after the filaments or other products leave the shrinking agent.

As suitable shrinking agents for use according to the present invention there'may be employed any substances or solutions or mixtures which have a swelling, solvent or latent solvent action -upon the cellulose derivative, for example acetic acid, formic acid, lactic acid, diacetone alcohol, acetone, the monoand di-ethers oresters or ether-esters oi olefine glycols or polyolefine glycols, for instance the monoand dimethyl and 1 ethyl ethers of ethylene glycol, glycol mono acetate, methyl glycol mono acetate, dioxane, the mono methyl and ethyl ethers of propylene glycol and the mono ethyl ethers of dietbylene glycol, etc. phenols, mono-, diand tri-acetins, dichlorethylene, ethyl lactate, diethyl tartrate and the like.

We have found, however, that it is especially advantageous to employ agents which at leastat ordinary temperatures are incapable of dissolving the cellulose derivative but which are capable of swelling the cellulose derivative in a high degree. Such agents, for example methylene chloride, ethylene chloride, chloroform, tetrachlorethane, ethyl acetate and the like, for usewith the ordi-' nary commercial acetone soluble cellulose acetate, usually become solvents for the cellulose derivative when mixed with a comparativelysmall proportion of another liquidand particularly an al-' cohol. Thus for instanceit is well known that methylene chloride, chloroform and tetrachlorethane in admixture with comparatively small proportions of alcohol are capable of dissolving' various cellulose acetates. The methylene chloride, tetrachlorethane and like agents are usually referred to as latent solvents for the cellulose de-f rivative, and will be so referred to in this specification. As already indicated, we find itparticularly advantageous to employ latent solvents in the process of the present invention.v Preferably the latent solvents are employed not mixed with alcohol or other agent capable of converting the said latent solvent into a true solvent, but either alone or mixed with 'diluents or substances which have little or no solvent or swelling action upon the cellulose derivative at ordinary temperatures. If however latent solvents are employed in conjunction with alcohols or similar acting substances, the proportions are preferably chosen so that a true solvent mixture is not formed.

The term organic solvent" as used hereinafter in the claims is to be construed as including within its scope both solvents and latent solvents for the cellulose derivatives.

Any suitable diluents may be employed both with latent or true solvents or with swelling agents, as for example glycol, glycerol or other hydroxy compounds. Preferably however, water immiscible liquids are used, examples of which are benzene, toluene, xylene and other cyclic hydrocarbons, benzine, petrol ether, kerosene and other hydrocarbons of the aliphatic or petroleum series, carbon tetrachloride, trichlorethyiene, perchlorethylene and other chlorinated or halogenated compounds which are inert or comparatively inert, towards the cellulose derivatives. Again relatively high boiling diluents, for example tetra-hydro-naphthalene and decahydro-naphthalene, may be employed. The particular agent and the concentration in which it is employed may of course be varied in accordance with the particular derivative of cellulose composing or contained in the filaments or other products, and with the ester or ether content of the said cellulose derivative. For convenience the treatment 01. the present invention will be hereinafter described more particularly with reference to the commercial acetone-soluble cellulose acetate, since at present this is the cellulose derivative which is of the greatest practical importance.

When filaments or other materials containing the said cellulose acetate are treated with pure methylene chloride, chloroform, tetrachlorethane or like latent solvents, it is found that if no tension be applied very considerable shrinkages occur, which may amount to as much as 70% of the initial length of the material. We find it preferable to efiect the treatment under such conditions that such high shrinkages do not occur, and in fact to carry out the process so that the shrinkages do not exceed about 15 or 20 or 25%. The restriction of. the shrinkage may be brought about by suitably diluting the shrinking agent with a diluent, as already described, and/or by effecting the treatment under a sumcient tension to prevent more than the desired shrinkage. As a further alternative the materials may be allowed to shrink by a considerable amount and be subsequentiy stretched. However, the best method of working is to employ the latent solvent or other shrinking agent in a concentration such that the amount of shrinkage produced in the absence of substantial tension is comparatively small, for example 10 to 20% of the initial length of the products. For any particular agent and conditions of treatment, the increase in the extension is dependent upon the extent of the shrinkage, so: that as a further criterion in determining the amount of shrinkage to be'permitted, one may have regard to the extension desired in the product, which as already indicated is preferably of the order of 10 to 20%. In the case of methylene chloride treatment of a yarn containing commercial acetone soluble cellulose acetate, we find that the best results are obtained with a 55 to 70 or 75% solution of methylene chloride in benzene, carbon tetrachloride or like diluent.

The shrinking agent may be applied to the materials in any desired manner, as for example by a bath treatment, in the form of vapour, or by spraying or padding methods. Shrinkage may.

take place during the treatment with the shrinking agent, or the material may be suitably impregnated with the shrinking agent and subsequently allowed to shrink. For the treatment with the shrinking agent the filaments, yarns, etc. may be loose, in the form of hanks, on bobbins, on s'wi'fts, in the form of a cake made by means of a centrifugal spimiing box, or in any other package form. By means of resilient bobbins,

swifts or supports, shrinkage may be permitted while the yarn is in the package form or alter-. natively the yarn may be wound off from the package, allowed to shrink and wound at a suitably slower winding speed so as to permit the desired amount of shrinkage. Thus, for example the yarn may be unwound from a bobbin, treated with the shrinking agent, carried through nip rollers and after a run, the length of which depends upon the time taken for the shrinking agent to act, carried through a second set of nip rollers rotating at a speed, relative to that of the first set, appropriate for the desired amount of shrinkage, and finally the filaments or yarns may be re-wound on any desired package. Similarly feed rollers may be substituted for the nip rollers described. Further, instead of allowing shrinkage to take place between rollers or other apparatus employed for that particular purpose,

suitable modifications, particularly with regard to speed, may be made in any apparatus normally employed in the treatment of the filaments, yarns or the like. Thus for instance instead of the amount of shrinkage being determined by the interposition of nip or feed rollers in front of a winding device, a drum winding device driven .at a suitable speedmay efl'ect the winding and allow shrinkage in a single operation. Again, by arranging that winding takes place on 3. bobbin or other package so that the yarns or threads are slack, shrinkage may take place on the package itself without the necessity for employing a resilient bobbin or the like.

Instead of unwinding from a bobbin or other package, filaments or yarns proceeding directly from a wet spinning process or from a stretching process may be treated. Thus .in the case of treating stretched yarn, the shrinkage characteristic of the present invention may be permitted to take place continuously with the stretching of the yarn. If desired the shrinking agent characteristic oi. the invention may be the agent employed to facilitate the stretching,. so that the yarn, for instance ordinary dry spun yarn, may be treated with the shrinking agent acting as a softening agent, stretched and without the removal of the agent allowed to shrink by the desired amount. Alternatively a suitable shrinking agent may be applied after the stretching process and continuously therewith, whether or not the agent applied to assist the stretching has been previously removed.

The shrinking process may, if desired, be carried out upon'yarn in warp formation, and may further be combined with a stretching process, as described for example in U. S. patent application S.-No. 602,844 filed 2nd April, 1932. Thus a warp of yarn which'has been stretched may then be allowed to shrink, the softening agentv remaining in the yarn being allowed to act as a shrinking agent, or the yarn may be treated with v additional quantities oi! the same or a difierent reagent in order to bring about shrinkage.

It will be seen that the present invention comprises broadly the treatment of yarns, filaments or other materials of cellulose esters or ethers having a relatively low extension with shrinking and also from cellulose ethers, as for example methyl cellulose, ethyl cellulose or benzyl cellulose, and from cellulose ether-esters, .may be treated. Moreover it is not essential that the material treated should consist wholly of a cellulose ester or'ether or a mixture thereof.

- The following examples are given in order to illustrate the invention, but it is to be clearly understood that they do not limit it in any way.

Example 1 A cellulose acetate yarn having a low extension produced by a wet j'spinning process or by stretching a dry spun yarn is immersed in hank form in a 1:4 mixture of methylene chloride. and dichlorethylene and allowed to shrink freely. After shrinkage the yarn is removed from the bath and dried without washing, yielding a product 01' improved extensibility.

Example 2 A low extension cellulose acetate yarn produced by a wet spinning process or by stretching a dry spun yarn is back-wound from bobbin shrink, and a product of improved extensibility is thus obtained.

Example 3 A wet spun cellulose acetate yarn, obtained for example, by any of the processes described in U. S. Patents Nos. 1, 465,994 and 1,467,493, U. S. patent applications S. Nos. 402,785 filed 26th October, 1929, 418,414 filed 3rd January, 1930 and 437,423 filed 20th March. 1930, U. S. patent application S. No. 601,043 filed March 24, 1932, corresponding to British application No. 13998/ 31 filed 12th May, 1931, and British Patents Nos. 340,436 and 340,437, is passed continuously with its production through a bath consisting of 20% toluene and 80% ethyl acetate and allowed to shrink. This may conveniently be carried out, for example, by passing it round a bobbin or spool having a certain peripheral velocity before its entry into the shrinking bath and collecting it after treatment on another bobbin or similar device having a lower peripheral velocity. A yarn of improved extensibility is thus obtained.

Example 4 A dry spun cellulose acetate yarn which has been subjected to a stretching process such as is described in U. S. patent applications S. Nos. 378,684 filed 16th July, 1929 and 573,424 filed 6th November, 1931, and U. S. patent application S. No. 605,184 filed April 14, 1932, corresponding 'to British application No. 1337 3/ 31 filed 6th May,

1931 is passed continuously with such process through a bath consisting of 75 methylene chloride and 25% tetrahydronaphthalene. It is taken up without washing on a spool or other device at a speed such that shrinkage can occur, and has acquired an increased extensibility.

It is to be understood that the stretching of the materials to increase their tenacity which is specified in the claims may, unless otherwise stated, have been carried out either during the production of the materials, or in an operation applied to the materials subsequent to their production.

What we claim and desire to secure by Letters Patent is:-

1. Process for increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materials having a basis of an organic derivative of cellulose and which have been stretched to increase their tenacity, which comprises treating such materials with a non-aqueous medium comprising an organic shrinking agent under a tension insufiicient to stretch them.

2. Process for increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materials having a basis of an organic derivative of cellulose and which have been stretchedto increase their tenacity, which comprises treating such materials with a non-aqueous medium comprising-an organic shrinking agent dissolved in a water-immiscible organic diluent under a tension insufficient to stretch them.

3. Process for increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materials having a basis of cellulose acetate and which have been stretched to increase their tenacity, which comprises shrinking such materials with a non-aqueous medium comprising an organic shrinking agent dissolved in a waterimmiscible organic diluent, the concentration of shrinking agent in the medium being such that under the shrinking conditions employed it is capable of shrinking the materials, in the absence of tension, by 10 to 20% of their original length.

4. Process for increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materials having a basis of an organic derivative of cellulose and which have been stretched to increase their tenacity, which comprises treating such materials, under a tension insufficient to stretch them, with a non-aqueous medium comprising an organic shrinking agent, which is a latent solvent for the cellulose derivative, dissolved in a water-immiscible'organic diluent.

5. Process for increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materials having a basis of cellulose acetate and which have been stretched to increase their tenacity, which comprises shrinking such materials with a non-aqueous medium comprising an organic shrinking agent, which is a latent solvent for the cellulose acetate, dissolved in a water-immiscible organic diluent, the concentration or latent solvent in the medium being such that under the shrinking conditions employed it is capable of shrinking the materials, in the absence of tension, by 10 to 20% of their original length.

6. Process for increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materials having a basis oi. an organic derivative of cellulose, which comprises shrinking such materials, which have been obtained by dry spinning processes and which have been stretched subsequent to their production to increase their tenacity, by treating them with a non-aqueous tate and which 4 medium comprising an organic shrinking agent dissolved in a water-immiscible diluentr '7. Process ior increasingthe dry extensibility oi artificial filaments, threads, yarns, ribbons medium comprising an organicshrinking agent dissolved in a'water-immiscible diluent.

8. Process for increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materialshaving a basis of cellulose acetheir tenacity, which comprises shrinking such materials by 10 to 20% of their original length with the aid of a. non-aqueous medium comprising a latent solvent for the cellulose acetate dissolved in' a water-immiscible diluent.

9. Process for increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materials having a basis of cellulose acetate and which have been stretched to increase their tenacity, which comprises shrinking such materials with the aid of a non-aqueous medium comprising a a halogenated hydrocarbon, which is a latent solvent for the cellulose acetate, dissolved in a water-immiscible diluent,"

10. Process for increasing, the dry, extensibility of artificial filaments, threads,- yarns, ribbons and like materials having a basis of cellulose acetate and which havebeen s'tretched to increase their tenacity, which comprises shrinking such materials with asolution of. methylene chloride in a water-immiscible organic diluent. 11. Process for-increasing the dry extensibility of artificial filaments, threads, yarns, ribbons and like materials having a basis of cellulose acetate and which have been stretched to increase their tenacity, which comprises shrinking such materials by 10 to 20% of their original length with the aid of a to solution of methylene chloride in a hydrocarbon diluent.

have been stretched to increase ,produced by treating ribbons and like materials,- which have been aqueous 12. Process for the production of artificial fiIaments, threads, yarns, ribbons and like materials having a basis of an organic derivative oi cellulose and having a high tenacity and good extensibility, which comprises stretching such materials with the aid of a swelling medium containing a high concentration 0! a swelling agent and then shrinking the stretched materials with a non-aqueous medium-comprising an organic shrinking agent dissolved in a water-immiscible organic'diluent.

13. Process for the production of artificial filaments, -threa.ds,: yarns, ribbons and like materials having a basis of cellulose acetate and having a high tenacity comprises stretching such materials with the aid of a swelling medium containing a high concentration of an organic swelling agent and then shrinking the stretched materials with a nonaqueous solved in a water-immiscible diluent.

14. Artificial filaments, threads, yarns, ribbons and like materials having a basis of an organic derivative of cellulose and having an extensibility of at least 12% and a tenacity of at least 2 grams per denier, produced by treating filaments,

threads, yarns, ribbons and like materials, which have been stretched to increase their tenacity, with non-aqueous media comprising organic shrinking agents dissolved in water-immiscible organic diluents.

15. Artificial filaments, threads, yarns, ribbons and like materials having a basis of cellulose acetate and having an extensibility of at least 12% and a tenacity of at least 2 grams perdenier, filaments, threads, yarns,

to increase their tenacity;- with nonmedia comprising organic shrinking agents, which are latent solvents for the cellulose acetate, dissolved in water-immiscible organic diluents.

WILLIAM PERCY FREDERICK stretched ALEXANDER DICKIE.

COMBE SOWTER.

and good extensibility, which medium comprising a latent solvent disline 6, claim 7, beginning with the word "and" strike out a obtained-by wet spinning processes,

- be read with these corrections therein that t =CERTI FICATE or co'finfsc'rioii.

Patent' No. 2,058,422, .October 27, is:

WILLIAM ALEXANDER DICKIiE, Er AL...

It is here y certified that error appears in the printed specification the above numbered patent requiring correction as follows: Page 2,. first column, line 51, .for "or" first occurrence, read to;- page4, first column 11 to and incl the word and comma rocesses,"in line 10, same claim, and insert instead comma and words which comprises shrinking such materials, which have be and which have been stretched to inc: t the said Letters Patent sh their tenacity during such processes; and the.

he same may conform to the 1 of the case in the Patent Office. U

Signed and sealed this 29th day of December, A. D. l936.

(Seal) Acting Commissioner of Eatent. 

